Valve



Patented Ian. 3, I899.

No. 6l7,2l4.

L. ALDRICH.

V A L V E (Application filed Doc. 2, 1887. Renewed Dec. 1, 1898.)

(No Model.)

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Witnesses.

Attorney.

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TATES Prion...

VALVE.

SPECIFICATION forming part of Letters Patent No. 617,214, dated January 3, 1899.

Application filed December 2, 1897. Renewed December 1, 1898. Serial No, 698,000. (No model.)

To all whom it may concern.-

Be it known that I, LoRIN ALDRICH, a citizen of the United States, residing at Indian Orchard, in the county of Hampden and State of Massachusetts, have invented certain new and useful Improvements in Straightway Valves; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to that class of straight way valves in which a gate or plug having tapered faces and movable in a plane perpendicular to the axis of the waterway is employed. It has been customary when such valves are to be used in connection with steam under high pressures to make the annular seats on the valve-body and the annular bearing-faceson the gate or plug of brass, com position bronze, or other similar material and to detachably secure said annular seats within the iron body of the valve by forming tapped recesses at the inner ends of the two branches of the waterway through said body, exteriorly threading the two annular seats, and screwing said seats into said recesses against a flanged shoulder at the inner end of the seat. Provision is thus made for con veniently removing the seats from the body when worn out and substituting new ones without necessitating the return of the valve to the manufacturer. The form of thread used on said seats and the valve-body has been the V-thread, and it has been found to be open to two serious objections-first, because it is practically an impossibility to make the inclined faces of the thread on the seat correspond with those of the thread on the body with sufficient exactness to. secure a steam-tight bearing between said faces, and, second, because the brass or composition seat has much greater expansive properties under the high temperatures to which these valves are subjected than the iron body, so that even if an approximately close fit between the threads is secured originally they are compressed or crushed by such unequal expansion to such an extent that after the first contraction of the parts by a reduced temperature a close fit between the threads is rendered an impossibility. As a result of such action of the \l-thread it has been found that the valves so constructed cannot be depended upon to carry steam under highpressures without leaki n g. I have discovered that these objections can be obviated and a renewable seat-valve provided which will carry steam under all pressures without leaking by providing the seat and the recess in the valvebody with a rectangular thread, the acting faces of which threads are perpendicular to the axis of the seat; and my invention consists in such construction of renewable seatvalves,as hereinafterfully described, and particularly pointed out in the claims.

Referring to the drawings, in which like letters and numerals designate like parts in both views, Figure 1 is a central longitudinal section of a valve embodying the invention. Fig. 2 is a cross-section of one of the annular seats.

The letter Ct designates the valve-body, having the Waterway 1) extending therethrough, c the gate or plug, having tapering faces carrying the annular bearing-surfaces d d, and e the gate-operating spindle, which is actuated by a hand-wheel (not shown) or other usual means to open and close the valve. At the inner endsof the two branches of the waterway are located the recesses ff, the axes of which are inclined to the axis of said waterway and perpendicular to the acting faces of the gate 0, as usual. Thewall of each of said recesses is tapped with a rectangular thread, as shown.

The letters 9 g designate the two annular seats, which terminate at their inner end in the annular bearing-face 2 to engage the an nular bearing-surfaces d on the gate and are provided exteriorly with a rectangular thread 3, which thread terminates at the inner end of the seat in the annular flange or shoulder i. Said seats are applied to the valve-body by screwing them into the recesses f f until the flange or shoulder 4t abuts against and makes a tight joint with the surface of the body surrounding the inner ends of the branches of the waterway, spanner projections 5 on the inner surface of the seats being provided for the purpose. The threaded portion of the seat is of less length than the depth of the recesses in the body, as shown, so that the former never bottom in the latter. It will be observed also by reference to Fig. 1 that the threads on the seats are of sufficiently less dimensions than those on the body to afford the necessary space at the edge and outer side of the threads on the seats to allow for the greater expansion of the seats without injury to said threads. When the seats thus constructed are seated in their operative position in the body, a steam-tight joint is formed not only between the flanges or shoulders 4 and the surface of the body at the margins of the waterway branches, but also between the inner face of each convolution of their threads and the parallel outer face of the threads on the body, the true parallelism of which faces cannot be affected by any expansion or contraction, however unequal the same may be. The multiplicity of steamtight joints thus secured absolutely prevents any leakage, regardless of the pressure of the steam with which the valve is used, while at the same time the seats are rendered as readily detachable and renewable as those here tofore used.

To prolong the effective life of the seat 9, I prefer to form its annular bearing-face 2 with a slight taper from its inner to its outer edge, as shown by the aid of abroken straight line in Fig. 2. By thus beveling the face of said seat it first engages and makesasteamtight ,joint with the annular face d of the gate at its inner edge, and as the face of the seat wears away its area of contact with the gate gradually widens until finally it embraces the entire width of the face 2, and from thenceforth until the seat is worn out the wear is equally distributed over the entire area of the face. In this manner I materially extend the life of the seat without impairing its steam-tight contact withthe' gate when the valve is shut.

The seats 9 will be composed of brass or composition and the valve-body a of iron, as heretofore; but by means of the invention herein described this form of renewable seatvalve, which has heretofore failed to hold suc cessfully steam under high pressures without leaking, is caused to successfully withstand such pressures without any sign of leakage.

Having thus fully described my invention, what I claim, and desire to secure by Letters Patent, is-

1. In a straightway valve, the combination with the iron body 0. having the waterway b and recesses f f in said waterway, the axes of which recesses are inclined to that of said waterway as described, and the walls of which recesses are tapped with a rectangular thread the side walls of which are perpendicular to the axes of the same, of the annular seats 9 9 having the bearing-face 2, rectangular thread 3 and flange or shoulder 4, and the gate 0 having inclined faces bearing the annular,bearing surfaces old which engage the faces 2 of said seats when the valve is shut, substantially as described.

2. The combination with the valve-body a having the rectangularly-threaided recesses f, and the gate 0, of the rectangularly-threaded seats 9 9 having the shoulders at and bearingfaces 2, said bearing-faces being inclined rearwardly from their inner to their outer edge, substantially as and for the purpose described.

In testimony whereof I affix my signature in presence of two witnesses.

LORIN ALDRICH.

Witnesses:

WM. H. CHAPMAN, J. B. HAMILTON. 

